Can't edit itunes information

Re: iTunes help

Hello everyones!

I Have been having some trouble with itunes, my sister and I both just bought ipods which each came with an itunes disc...Hers lets her change song information in itunes computer... but on my computer when i try to edit song information in itunes the info is just gray and wont let me edit it...Why is this? and what can i do that will allow me to edit all the song information ...I have no idea what to do...please help...